1. Field of the Invention
The present invention relates to an inductance element used in electric equipment such as a cellular phone, a digital camera, a mobile device, a laptop personal computer and the like.
2. Description of the Related Art
In recent years, inductance elements are demanded further downsizing and height reduction. In addition, the inductance elements are further demanded to have a resistance to shocks applied from outside when mounted onto a variety of electric equipment. Meanwhile, the inductance elements can be divided into various types. Out of the various types, Japanese Patent Application Laid-Open No. 2005-285901 (Patent document 1) (refer to abstract, FIG. 1, FIG. 2 and so on) discloses one type having a structure in which a wiring frame portion of a drum core has a coil, and a ring core is arranged around the coil, and further cup terminals are arranged around the outer peripheral sides of the ring core. On the other side, in Japanese Patent Application Laid-Open No. 2005-150470 (Patent document 2) (refer to paragraph #0017, FIG. 1 and so on), a structure, in which a coil is arranged at a T-shaped core and a resin layer coats the peripheral of these T-shaped core and the coil, is disclosed.
As described above, the inductance elements are demanded further downsizing and height reduction. In addition, the inductance elements are further demand the reduction in the number of parts, and the steps and costs in their manufacturing.
Here, in the structure disclosed in Patent document 1, a core of a ring shape (ring core) is arranged around a drum core. In addition to that, an adhesive is applied on the surfaces of the cup terminals and the drum core, and the cup terminals and the ring core are jointed via the adhesive. Therefore, the number of the parts increases due to the existence of the ring core, and the cost also increases thereby. Further, the number of steps increases so as to bond the ring core, which also increases the costs.
Furthermore, in Patent document 1, at the inner peripheral side of the cup terminals, the drum core and the ring core are arranged. Here, the cup terminal has a bottom portion and the outer peripheral side of the bottom portion is provided to follow an arc shape. Therefore, the outer diameter of the cup terminal comes to be larger than the drum core and the ring core, in which the inductance element is put into the state against the demand of downsizing.
Further, in the structure disclosed in Patent document 2, an exterior resin layer containing magnetic powders is provided to coat the wire. However, when forming the exterior resin layer, it is needed to be formed separately using a formwork or the like, requiring an additional fixture or the like. Therefore, the cost increases due to the required fixture. Further, when forming the coil, the wiring guide is required. Therefore, in comparison with the case where the wiring is wound directly around the winding frame portion, the cost increases due to the required wiring guide, in which working efficiency degrades as well. Moreover, after the coil and the exterior resin layer are formed, a work cutting them into two pieces is required as well.